Selective RNAi silencing of Schwann cell Piezo1 alleviates mechanical hypersensitization following peripheral nerve injury

The present study was designed to investigate the role of Schwann cell (SC) Piezo1 in peripheral nociception. We first developed an AAV vector that has primary SC tropism after delivery into the sciatic (or tibial) nerve. This was achieved by packing AAV-GFP transcribed by a CBA promoter using a capsid AAVolig001 to generate AAVolig001-CBA-GFP. Six weeks after intraneural injection of AAVolig001-CBA-GFP in naive rats, GFP expression was detected selectively in both myelinating SCs (mSCs) and non-myelinating SCs (nmSCs). A dual promoter and bidirectional AAV encoding a U6-driven short hairpin RNA against rat Piezo1 (PZ1shRNA) and CBA-transcribed GFP was packed with capsid olig001 (AAVolig001-PZ1shRNA), and AAV was injected into unilateral sciatic (or tibial) nerve immediately after induction of common peroneal nerve injury (CPNI). Results showed that the development of mechanical hypersensitivity in the CPNI rats injected with AAVolig001-PZ1shRNA was mitigated compared to rats subjected to AAVolig001-scramble. Selective in vivo SC transduction and functional block of Piezo1 channel activity of primary cultured SCs was confirmed. These data demonstrate that (1) AAVolig001 has unique and selective primary tropism to SCs via intraneural delivery, and (2) SC Piezo1 contributes to mechanical hypersensitivity following nerve injury.